All the ground state geometries as well as ground state electronic structures are calculated
using the QUANTUM ESPRESSO (QE) code [1]} which is a plane
wave based implementation of density functional theory (DFT).
BFGS scheme has been used to obtain the relaxed structures.
For bulk systems variable cell relaxation has been performed to optimize lattice parameters and ionic positions.
A separation of at least 10 Å between periodic images has been ensured for all the finite systems.
The KS ground state properties are calculated within the Perdew-Zunger approximation of the
exchange-correlation functional implemented in a norm-conserving pseudo-potential.
Plane wave basis with kinetic energy cutoff in excess of 60 Rydberg
along with a 15x15x15 Monkhorst-Pack grid of k-points have been used for all the bulk systems.
The self-energy correction to KS energy eigenvalues are calculated at the G\(_0\) W\(_0\)  level of
GW approximation of the many-body perturbation theory (MBPT)
implemented in the BerkeleyGW (BGW) code[2]}. To calculate the static dielectric matrix and extend to the finite
frequencies the generalized plasmon-pole model [3]} is used.
For convergence of dielectric function as well as the self-energy term
we used in excess of 250(5000) bands for bulks(nano-diamonds). To get a well converged band-gap for bulk
structures we used a finner k-mesh of 30x30x30 grid.
Finally, in-house implementation interfaced with the QE code is used for generation of HAOs, HAWOs
from KS states, calculation of TB parameters in the HAWO basis,
and mapping of TB parameters from smaller reference systems to larger target systems.
